I'm reading the book for the second time and enjoy the re-reading very much until now. I have a (maybe silly) question, but the answer seems very important for the morals of the book.
I don't understand exactly why is it sooo wrong that the young people in Mansfield Park are having a theatre performance? Is it more a general question of decorum (grown ups of the gentry or higher circles don't do this, for children it was allowed and encouraged) or is it specifically because they take such a possession of the house of Sir Thomas in his absence?